Posts

Reading "State Estimation and Control of Electric Loads to Manage Real Time Energy Imbalance"

AbstractCoordinate aggregation of thermostatically controlled loads (TCLs) to manage frequency and energy imbalance in power systems GoalCentral management of loads with high accuracy with low maintenance communication and sensing infra Load State Info (Power consumption and temperature) MethodologyMarkov Chain ModelsTemperature state evolution of population of TCLsKalman FilteringState and joint parameter / state estimationLook ahead proportional controllerBroadcasts control signals to all TCLsResultsPower tracking RMS errors Generator copmliance thresholdIntroElectric loads are participating in DR programsimprove electric grid reliability and reduce wholesale electricity pricesResearchTraditional research: strategies to decrease power use in the event of loss of generation or high pricesRecent: Incorporate local load states into control decisions to enable non disruptive load reductions This paper: Also nondisruptive controlFor the purpose of delivering services such as load followi…

Empirical Characterization and Modeling of Electrical Loads in Smart Homes

8:40 AbstractPrereq for data analysis of electricity usage - modeling of how electrical loads use powerEmpirical approach: Monitor common loads to distill common usage characteristics in order to construct accurate load-specific modelsModel is more accurate than simple on and offTwo uses of models in data analysisgenerate device-accurate synthetic traces of electricit usagefilter out loads that generate rapid & random power variationsIntroComputing for sustainabilityPhysical infrastructure leveraging sensing & networking & computation Building energy efficiencyBuilding accnt for 40% as opposed to 1-2% for IT infra Buildings consume electricity (73% of total energy)Existing management techniquesSense-analyze-respondSensor via smart meter & Transmit data to serversAnalyze occupancy patternResponse by controlling electrical loadsSensors are expensiveCan we analyze better? On and off modelslight bulbs & low power resistive devices w switchesbuildings can be modeled as …

Reading "Trade-offs and efficiencies in optimal budget-constrained multispecies corridor networks"

AbstractCurrent approach for connection conservation areas through corridors -> single optimization goal of maximizing movementlinkages can be too expensive  tradeoffs between expense and ecological benefits"Budget"; optimize given a specific budgetIntroProtected areas for widelife habitatIsolated safe haven: Not sufficient on its own for long term maintenanceHabitat connectivity: Key priority for government agenciesCorridors can help migration and prevent negative genetic / demographic impacts of isolation Identifying corridorsCommon approach: Develop landscape resistance surfaceRequires assigning costs via various methods (expert opinion, genetic distance, estimating costs from mark-recapture, etc)Distance between locationsLeast costResistanceHigher resistance = more difficult path for animals Pinch pointsdispersal paths overlap BCD Problem (Budget-constrained corridor design) Spatially explicit models of species-specific resistanceSpatially heterogeneous economic costs…

Reading "How Does Eco-Coaching Help to Save Energy? Assessing a Recommendation System for Energy-Efficient Thermostat Scheduling"

AbstractEco coaching: Field deployment for exploring a design approach; for specific actions that would reduce wasted energy. ThermoCoach: Eco-coaching for thermostat scheduling.Senses and models occupancy patterns in a home & provides suggestions for configuring thermostatEco coaching accomplishes four thingsUsers can implement effective thermostat scheduleIt supported user agency in negotiating energy savings and goalsFacilitated learning different scheduling strategies and weighing different optionsChallenged user beliefs about how well they were doing. IntroTechnology in helping energy savingEco-feedbackGive info about energy usageSome actions are too complex or time consuming AutomationSave energy on users behalfNot work as well (why?) Eco-coachingOne step more than eco-feedback; provide feedback based on past data but also identify waste and recommend actions to prevent energy waste in the future. One step less than automationMixed initiativeThermocoachdeployment of eco coac…

Reading "High-dimensional Time Series Clustering via Cross-Predictability"

AbstractTime series clustering : similarity metric is key"Cross-predictability" -> new metric proposed by this paper; degree to which a future value in each time series is predicted by past values of the others. Challenging in high-dimensional regime -> Sparsity assumption (only time-series in the same cluster have significant cross-predictability)This paper = first practical high-dimensional time-series clustering with a provable guaranteeIntroIn IoT, # sensors >> # readings in the time series (d >> T); under-constrained (d variables and T equations) Time series clustering metrics -> either not provable or considers non-high dimensional"cross-predictability" : how much a future value is predicted by past values of the others Captures causal relationships between time seriesDeal with under-constrained problem with sparsity assumption (only time series in the same cluster have significant cross-predictability with each other)Regularized Dantzig …

Reading "Transferring Decomposed Tensors for Scalable Energy Breakdown across Regions"

AbstractEnergy breakdown solutions require (1) instrumentation (2) model training for each geographical region This paperRegion independent energy breakdown model via statistical transfer learningIntuitionHeterogeneity in homes and weathers across different regions most significantly impacts the energy consumption across regions Factor out heterogeneity to learn homogeneous energy breakdown components for each individual appliance.Transfer model learned in one region to another regionIntroductionEnergy breakdown benefits -> energy saving, load forecasting, improving design, policy makingHow to energy breakdownMetering hardware appliance-levelNILM -> Hardware home-level, source separationNNMF -> Benefit: Similar instrumentidea: Similar homes have similar per-appliance energy breakdown. So, estimate breakdown of a home based on a similar home which already has breakdown available. Problem: Has IID assumption between test / training and requires testing home to be similar to tra…

Reading "Matrix Factorisation for Scalable Energy Breakdown"

AbstractEnergy breakdown is a valuable information for reducing energy consumption Existing approaches = expensive, requires hardwareThis paperFeature based matrix factorization for handling repeating structure in energy data due to common design and construction patterns Evaluate on 516 homes from public data; better than 5 baselines Deployment of system as a live web application to provide energy breakdown IntroImportance of energy breakdownEnergy breakdown is expensive Domain: collaborative filtering through feature-based matrix factorization for energy breakdownDataport data set with 516 homes Related workScalability of energy breakdown with (1) metering hardware (2) energy disaggregation techniques ; they all require hardware Direct load metering - requires power meter DisaggregationInfer the power of energy of individual loads based on aggregate power measurements Under-constrained problem.Requires source separation techniques Requires meter per building gathering data at freque…